Baragon 
Baragon is a system for automating load balancer configuration updates. It pairs well with the Singularity Mesos framework.
Contents
Baragon Basics
Baragon is made up of two services:
-
BaragonService -- coordination service
-
BaragonAgentService -- applies changes on the actual load balancer
When a web service changes (i.e. upstreams added / removed), POST a BaragonRequest JSON object to BaragonService's /[contextPath]/request endpoint like this one:
{
"loadBalancerRequestId": "4",
"loadBalancerService": {
"serviceId": "1",
"owners": ["foo"],
"serviceBasePath": "/basepath",
"loadBalancerGroups": ["loadBalancerGroupName"]
},
"addUpstreams": ["1.1.1.1:80"],
"removeUpstreams": []
}
BaragonServicewill fan out the update to allBaragonAgents in the specifiedloadBalancerGroupsBaragonAgents will apply the changes on the load balancer using templates provided in its configuration and report back a Success or Failure toBaragonService- Polling the
BaragonServicerequest status url (/[contextPath]/request/{loadBalancerRequestId}) will indicate the current status of the request
Check out the API Docs for additional BaragonRequest fields and returned values.
Getting Started
For more details on configuring and using Baragon, check out the detailed setup and management guide
** Prerequisite: A working ZooKeeper cluster **
-
Build JARs via
mvn clean package. -
Create a configuration file for Baragon Service and Baragon Agent. These are an extended version of a Dropwizard configuration file. Details on configurable fields can be found in the example configs below and in the detailed setup and management guide
- Example Baragon Service Configuration. This will be referenced as
$SERVICE_CONFIG_YAML. - Example Baragon Agent Configuration. This will be referenced as
$AGENT_CONFIG_YAML.
-
Copy
BaragonService-*-SNAPSHOT.jarand$SERVICE_CONFIG_YAMLonto one or more hosts, and start the service viajava -jar BaragonService-*-SNAPSHOT.jar server $SERVICE_CONFIG_YAML. -
Copy
BaragonAgentService-*-SNAPSHOT.jarand$AGENT_CONFIG_YAMLonto each of your load balancer hosts. Start the BaragonAgent service viajava -jar BaragonAgentService-*-SNAPSHOT.jar server $AGENT_CONFIG_YAML.
Quickstart with Docker Compose
To get an example cluster up and running, you can install docker and docker-compose.
Simply run docker-compose up to bring up:
- zookeper container
- Baragon Service container
- Two Baragon Agent + Nginx containers
The Baragon UI will be available at localhost:8080 and nginx at localhost:80.
If using boot2docker replace localhost with the boot2docker ip
Nginx's config directories that BaragonAgent writes to will also be mounted as volumes in the docker/configs folder on your local machine.
BaragonUI
Baragon comes with a UI for visualization and easier management of load balancer paths and upstreams. By default it will be available in a read-only mode at /[contextPath]/ui see the Example Baragon Service Configuration or detailed setup and management guide for more details on configuring BaragonUI behavior.
Baragon API Docs
Full documentation on the Baragon Service API can be found here